Selective control apparatus for radio systems and the like



R. W. MAY SELECTIVE CONTROL APPARATBS FOR May i7, 1949. 2,410,561

RADIO SYSTEMS AND THE LIKE v4 Sheets-Sheet l Filed April 26, 1946 INVENTOR. HCH/4P@ M/ W4 T/P/Vf/ May 17, 1949. R. w. MAY 2,470,567

SELECTIVE CONTROL APPARATUS FOR RADIO SYSTEMS AND THE LIKE Filed April 26, 1946 4 Sheets-Sheet 2 INVENTOR.

R. W. MAY sELEcTIvE CONTROL APPARATUS FOR May 17, 1949. 2,470,567

RADIO SYSTEMS AND THE LIKE 4 Shasta-Sheet 3 Filed April 26, 1946 www i. Aw WMI. uN

JO, u km May 17, 1949. R. w. MAY sELEcTlvE coNTnoL APPARATUS Fon RADIO SYSTEMS AND THE LIKE 4 sheet-sheet 4 Filed April 26, 1946 Patented May 17, 1949 arroser SELETIVE CONTRIL PPARATUS FOB; BABE() SYSTEMS AND THE LIKE Richard W. May, Cedar Rapids, Iowa, assignor to f Collins Radio Company, Cedar corporation of iowa Rapidalowa, a

Application April. 26, 19%, Seriali No. 665,107

of the invention can be embodied in any apparatus which is required to determine with utmost accuracy the angular orientation of a control shaft.

The invention is in the nature of an improvement upon the type of tuning control mechanism disclosed and claimed in application Serial'No. 515,250, filed December 22, 1943, and in various prior issued patents of Arthur A. Collins of which Patent #2,285,414, granted June 9, 1942, is typical. in certain kinds of radio'equipment employing a control shaft, such for example as a tuning condenser shaft, the complete tuning range can h eil'ected by a. single complete rotation of the s aft. which the well-known permeability or slug tuner is typical, the tuning motion is rectilinear and usually requires a control shaft which must bev capable of undergoing more than one complete rotation in order to cause the tuning element to move over its complete positional tuning range. For simplicity of reference, the first type f device wlllbe referred to herein as a single turn selecting control, and the second will be referred to as a multi-turn selecting control.

Accordingly, it is a principal object of this invention to provide an arrangement for automatically and selectively controlling the angular positioning of a control shaft regardless o f whether the shaft is required to make more than one complete rotation or only a fractional rotation.

It is also an object voi' the invention to provide composite electrical and mechanical controls for selectively operating a -multl-turn control shaft employing a single selector switch having a series of bank contacts each corresponding-to a desired angular position of the said shaft.

Another object of the invention is to provide an improved composite electrical and mechanical control device for selectively setting a multi-turn control shaft.

It is a further object of this invention to pro- 22 anims. (criss-itz) vide two similar automatic shaft positioner control units at least one of which is of the singleturn control typathe units being interrelated so that the shaft to be controlled can loe selectively rotated through more than one complete rotation before being selectively stopped in its final selected position.

A feature of the invention relates to a selectivev l A shaft'positioning arrangement comprising two selectively operable units each of the type having a series of stop elements which can be preset to anyJdesired angular settings, and a series of selective cam-controlled pawls which cooperate with said elements to determine the selective stopping thereof. :The arrangement is such that the. two units can be selectively stopped in timed succession, the lrst unit determining'thenumber of vcomplete rotations desired for the control shaft, and the second unitdetermining the particular rotational increment required to reach the final selected.l shaft position.

In other kinds of radio equipment of n Another feature relates to a selective shaft positioning arrangement employing a plurality of shaft stopping units which can be selectively stopped in any desired angular-orientation, the units being interrelated by-a dierential drive whereby one unit determines the number of complete rotations of the control shaft and the other unit determines the incremental angular rotations to which the shaftmust be moved to its final selected position.

A still further feature relates to the novel organization, `arrangement and inter-connection of parts which cooperate to produce an improved positional control' system for a multitum control shaft.

Other objects, features and advantages not particularly' enumerated will be apparent after a consideration of theY following detailed descriptions and the appended claims.

In the drawing, l

Fig. 1 is a top-plan view ofan embodiment ci one of the positioning units according to the invention.

Fig. 2 is a cross-sectional view along line 2--3 viewed in the direction of the arrows.

Fig. 3 is a bottom view of the device of Fig. i..

Fig. 4 is adeveloped schematic diagram showing more clearly the mechanical 'arrangement of` the shaft control system.

Fig. 5 is a schematic -electric circuit diagram of a suitable electric control circuit, with the mechanical arrangement shown in block diagrammatic form.v f'

Fig. 6 is a sectional view of Fig. 1 taken along 3 the line 6-6 thereof and viewed in the direction of the arrows.

Fig. 7 is an assembly view of the two units and their respective interconnections as schematically illustrated in Fig. 4.

This invention makes use of two single turn control devices modified and interrelated to obtain multi-tum control and thereby effecting a simplification over devices normally used to obtain such multi-turn control. A single turn control device Which readily lends itself to multi-turn operation in accordance with this invention, is described in detail in application Serial No. 515,- 250, led December 22, 1943, to which reference is hereby made.

'According to the present invention, two singleturn control devices are employed and modified and arranged for synchronized operation by the addition of suitable mechanical synchronizing means, The stop means disclosed in said application for limiting the shaft to one rotation is removed from one device, and the other device is identical with that disclosed in said application Serial No. 515,250.

Referring more particularly to Figs. 1, 2 and 3, the tuning control device is arranged as a selfcontaine'd unit mounted between end plates III and II held in appropriate relationship by tie rods I2, I3, I4. Shaft I5 represents the tuning control shaft whose rotation is to be selectively controlled, and it is provided with suitable ball bearings I6 in the plates III, II. A drum I1 is mounted -on shaft I5 and has a clamping ring I8 which is capable of. axial sliding movement along the shaft by being suitably keyed thereto. The clamping pressure on ring I8 is controlled by a rotatable barsIQ associated with a stud (not shown) coaxial with shaft I5 and vthreaded therein so as to cooperate with member I8. Dial knob 25 is flxedly mounted on shaft I5 externally of the end plate II. Drum I1 rotatably supports on its periphery the desired number of stop rings 2IA-2IL, which are appropriately spaced along the drum by spacer washers 22A-22K. The stop rings and spacers are axially movable along the periphery of the drum and are arranged to be clamped together by clockwise rotation of bar I 9 which causes the rim of member I8 to be displaced to the right as viewed in Fig. l. The clamping pressure at the opposite end of the series, being against a flange (not shown) on drum I1.

Each of the Stop rings 2IA-2IL has a peripheral notch 23A-ML, and the peripheral orientation of each notch relative to shaft I5 determines a corresponding angular stopping position of that shaft when the stop ring containing that particular notch is stopped by a previously selected pawl. Bar I9 provides means for loosening the stop rings on drum I5 so as to allow them to be independently and manually preset to the desired angular orientation around shaft I5 and to be locked in'that position. Ob-

the recesses being arranged so that they form a helical path around the periphery of barrel 25. As aresult of this helical arrangement of l the recesses, only one of' the previously mentioned of the washer.

stop rings can be selectively stopped at any given time, these recesses serving to preselect a particular one of a series of lcooperating pawls 25A-25L. Pawls 26A-26L are mounted in appropriately spaced relation on, and for independent oscillation around, shaft 21 (Fig. 2) arranged parallel to shaft 24. Each of the pawls is planarly aligned with a corresponding stop ring and with a corresponding cam. For example, the particular pawl 26A which will be used subsequently for purposes of description in connection with Fig. 4, is aligned with coacting cam 25A and cooperating stop ring- 2IA. Each pawl is provided with one of a series of wire springs 28A-.28L, each spring being looped around the liixed rod 29 and having its lower end (Fig. 2) in engagement with the rectangular bar 30 extending between the plates I5 and II. The upper end of each spring engages the edge of the corresponding pawl thus tending to rotate the pawl counterclockwise as seen in Fig. 2. Each pawl has a toe 3l and a heel 32. The toes are adapted to coact with the notches in the stop rings, while the heels are adapted to cooperate with the slots in the peripheries of the respective cams. It is clear therefore, that the toe of any pawl cannot completely enter a notch in the corresponding stop ring until the heel of that pawl is riding on the lowest portion on the slot of an associated cam. Fig. 2 shows the mechanism wherein the pawl 28K is in selected position so that its heel 32 rests on the low portion of the slot in the associated cam, while the toe 3l is in full registry with the corresponding notch 23K. In this position each remaining pawl, for example -pawl 28L, has its heel resting on the non-slotted periphery of the associated cam, thus preventing the toe of the pawl from registering with a notch in the corresponding stop wheel. When any pawl has its toe 3l in complete registry with a notch such as 23K, it effectively locks that particular stop ring against any further rotation. Consequently, the stop ring drum I'l is positively and accurately stopped in the selected position corresponding to that to which the tuning element is to be adjusted. While the tuning shaft is thus positively stoppedfthe driving motor may continue to rotate because it is coupled to the shaft I5 through a slip friction clutch 32.

A suitable motor 42 schematically illustrated in Figs. 4 and 5, drives gear 33 which in turn drives shaft I5 through the intermediary of slip clutch 32. Gear 35 is rigidly connected to gear 33 and meshes with gear 35 which drives a lost motion device 31 interposed between the cam barrel shaft 24 and the gear 35. Device 31 drives the element 38 which also drives the selector cam barrel 25. The device 3l may take any form well-known inthe art and may consist, for example, of a series of washers 31a-31f (Fig. 6), each washer having a pair of diametrically opposite lugs which are off-set in opposite directions from the plane The first washer of the series can be connected to the gear 36, and the remaining washers except the last of the series, are free to rotate around the shaft 24. The last washer of the series is connected to shaft 24. By this arrangement, a series of complete revolutions of gear 36 are necessary before the shaft 24 begins to rotate, it being understood that the gear 36 is not keyed or otherwise fastened to shaft 24.

For a detailed description of the construction of a preferred form of lost motion device 31, reference may be had to said application Serial No. 515,250, it being understood that the device 31 is designed with suilicient time delay so as to coordinate the various controls as will be described hereinafter. Terminal stop pawl 39 is mounted on fixed shaft 21, so as to conne the rotation of the corresponding terminal stop ring 4I to an angular orientation of approximately 360 degrees. Terminal stop ring 4I is keyed to shaft of drum I1 and cooperates with pawl 39.

When using one of these control devices for positioning a single turn shaft such as that of a tuning condenser or the like, the shaft which drives gear 33 also drives a suitable limit switchY and a suitable multi-point selector switch, both of which are schematically illustrated in Figs. 4 and 5 and designated respectively therein by the numerals 49 and 50. The limit switch 49 is directly driven from the above-mentioned shaft while the selector switch 50 is driven through. a lost motion device 5| similar to the device 31, so as to provide the necessary time delay in coordinating the various selective functions to vbe described. The limit switch 49 comprises a rotatable member having a pin which cooperates with a snap switch arm so that when the pin is at one limit of its movement, it closes one set of contacts and opens the other set, and vice versa, when the said pin is at the opposite limit of its movement.

The selector switch 50 is of the usual line nder type having a rotatable .brush which .is

.driven by the same motor Awhich drives the shafts 2 4 and I 5. This switch is provided with a series of bank contacts which are multipled to the corresponding flxed contacts of a manually rotatable selector switch, the brush arm of which is grounded. In accordance with well-known line finder principles, the grounding of any contact -in the manual switch applies a ground to the correl spending bank contact of the selector switch, and when the cycle of operations is at a predetermined point to be described, the switch motor is set into operation and causes the selector switch to seekvthe previously grounded bank contact. The stationary bank contacts of the selector switch correspond respectively to the selector cams 25A-25L, the arrangement being such that when the rotary brush of the selector switch finds prises the requisite vnumber of stop rings, selector the particular grounded contact of its bank of contacts, the common motor comes to a stop as does the cam barrel 25 in a predetermined angular orientation which in turn determines the selection of one of the corresponding pawls 28A-NL. The motor then reverses its direction of rotation but without affecting the selected stopped position of barrel 25. For a detailed description of the functioning of the various parts described hereinabove, reference may be had to said application Serial No. 515,250. The foregoing described structure functions as described in said application normally as a single turn selector control device.y In accordance with the present invention, a pair of such devices are combined to achieve the effect of a multi-turn selector. In order to achieve this result, it is neces-` sponding to the schematic view of Fig. 4. The

cams and associated pawls. v

Both unit #I and unit #2 are lpowered from the same driving motor 42 (Figs. 4 and 5) whichmay be of the direct .current reversible type. Unit #2 is driven through a lost motion device 43 which may be similar to device 31 (Fig. 1), it being designed to provide the appropriate time delay be tween the rotation of the stop ring drum I1' of unit #I and the stop ring drum I1" of unit#2.

Shaft 46 provides direct drive through slip clutches 32' and 32" to the stop ring drums I1' and I1 respectively, and worm gears 41 and 43 drive the limit switch 49 and the multi-point selector switch 50 respectively.

Stop ring shafts I5' and I5" of units I and` 2 respectively cooperate, in accordance with the invention, with a device which controls the desired rotational relations between the two stop I drums. This means is diagrammatically illustrated in Fig.- 4 in the form of a differential link, the extent and direction of rotation of which is determined by the relative movements of the two shafts I5' and I5". This differential link may comprise for example a planetary gear system 53, the planetary gears 54 of which are coupled t0 shaft I 5' through idler gears 5I, the idler gear shafts being indicated schematically by numerals 5,6 and 51. In the drawing, the various shaft interconnections are represented by dotdash lines. The sun gear 58 is coupled to shaft I6" of unit #2 as indicated by numeral 5l; ring` gear 60 is connected to a rotatable disc 5I which carries a ratchet arm B2 pivotally mounted on the disc 6Il at 63 and normally biased by spring 64 in a clockwise direction against thestop carried by the disc. Extending parallel to the axis of the disc 6I is a fixed shaft 88 onwhich is pivotally mounted an anvil 51. This anvil has at its left-hand end a downwardly depending lip or flange which overlies and extends across all the pawls 26A"26L". The anvil 61 is normally biasedby means of the tension spring 6! so as to maintain the lip 68 in position between the end of the pawl toes and the associated stop rings -when the pawls are in non-selected position. In

. be housed in a separate unit represented by the dotted outline 10, which can be appropriately attached to unit #2 as indicated in Fig. 2

In Fig. 4, there is'illustrated a device 1I which is to be adjusted to any one of a large number of selected positions. For example, device 1I may be any well-known form of permability or slug tuner, comprising a tubular inductance winding, and a slidable magnetic core whose extent of telescopic adjustment determines the effective inductance. Because of the linear movement of this core. it is usually necessary to employ some kind of lead screw and follower. Likewise, becauseof the critical nature of tuning, the

llead screw must be capable of a considerable number of rotations. In Fig. 4, line 12 represents the shaft which is connected tothe lead screw, and it is therefore necessary to determine with extreme accuracy the total angular orientation of the shaft, which may vary from a very small fraction of one rotatin t 21rn-i-a, where n is the total number of complete rotations and a is the additional fractional rotation necessary to achieve nal selective positioning of device 1|.

The selecting of the desired channel, i. e., the channel determined by the desired setting of device 1|, is effected by moving switch arm 14 to ground the appropriate channel contact, e. g., contact 15 (Fig. 5). The bank contacts of switch 13 are multiplied to corresponding bank contacts of the automatic switch 50, which loperates on the wellwknown line finder principle. It should be observed that the motor start relay 16 remains energized during the entire time that the equipment remains at rest in a selected position. This normal circuit for relay 16 is traceable from the grounded brush 14 through the multiplied bank contacts of switches 13 and 50, brush 11, closed contacts 18 of the end limit control switch 49, winding of relay 16 and thence to the grounded battery 19. As long as relay 16 is thus operated it opens the power circuit of motor 42 at contacts 80. When a new channel selection is desired, the movement of brush 14 to a different contact opens this circuit for relay 16. As soon as relay 16 deenergizes it closes a circuit traceable from ground through the armature of motor 42, contacts 86 of relay 16 and thence to ground through battery 19. The direction of rotation of the motor 42 is determined by the condition of the motor reversing relay 8|. In the particular condition as illustrated in Fig. 5, the directional winding 82 of vthe -motor is energized from ground through that winding, thence through the back contact 83 and armature 84 of relay 8| to the grounded battery through contacts 80 of relay 16. This direction of the motor rotation continues until the rotatable element of the end limit switch 49 rotates sumciently to cause the pin 85 to close the contacts 86, and brush 11 makes contact with vthegrounded terminal. Under the above described conditions, it will be assumed that the motor 42 begins to rotate the stop drum shaft I' of unit #I in a counterclockwise or homing direction. It will be observed however, that the brush 11 of the nder switch does not immediately start to rotate at the same time as shaft I5 because of the lost motion device 5| which is interposed between the gear 52 and the' shaft of switch 59. This lost motion device is designed so as to provide sufficient time delay after the initiation of the motor rotation, to enable the shaft I5' to rotate sufllclently to cause the stop tooth 40 to engage the limiting stop pawl 39 representing the home position of unit #L Likewise, the cam barrel 25' starts rotating a timed interval after the beginning of rotation of the motor by reason of the lost motion device 31. lAs-soon as the cam barrel 25 starts to rotate counterclockwise, it causes a previously selected pawl e. g. 26A' to be rotated clockwise against the action of its associated spring, thus permitting the stop ring drum l1' to rotate ina counterclockwise direction. This rotation continues until the stop lug 40 on the terminal stop ring 4| engages the limiting stop lug 39, as above described. At the same time that motor," begins to rotate, it rotates the control element,\of the limit switch 49 in a counterclock- 31 and 31".

, 8 y wise direction. Almost immediately after be ning of motor rotation contact 18 is opened. Shortly thereafter contact 86 becomes closed allowing the circuit to be completed through switch and brush 11.

After a timed interval determined by the delay design of the lost motion device 5|, the brush 11 starts rotating to seek the grounded terminal in its contact bank, which when found thereby simultaneously determines the selective stopping position of drum 25'. Likewise, there is a predetermined time delay between the starting of the motor rotation and the starting of shaft I5, this delay being introduced by the lost motions device 31" and 43. This lost motion is required because unit #I must set up its position, thereby determining the position of disc 6I and latch 62 before unit #2 begins its set-,up cycle. When lug 40 engages stop 39, stop ring drum I1' stops rotating allowing clutch 32' to slip. While the stop ring drum I1' is thus stopped the lost motion devices 31', 31 and 5| have now taken up; and the cam barrels 25 and 25 rotate counterclockwise in synchronism with switch 50. When brush 11 comes to rest on the selected grounded contact of switch 50, it closes a circuit traceable through the contacts 86 of the home linut switch thence through the winding of motor reverse relay 8| to the grounded battery 19. Relay 8| thereupon connects the reversing motor eld winding 81 in circuit and the motor stops, as does the drum 25', and then the motor begins to rotate in the opposite direction. During the reverse rotation of the motor the previously selected stopping position of drum 25 is not disturbed because of the action of the lost-motion device 31'.

As the stop ring drum I1' was being turned counterclockwise to home position as above described, the disc 6| was rotated in a clockwise direction through the intermediary of differential 53, thus removing the ratchet 62 away from anvil 61. After a short interval determined by lost motion device 43, the stop ring drum I1" begins to rotate counterclockwise in its homing direction causing the member 53 to rotate in a clockwise direction. After another short interval determined by device 31", the cam barrel 25" rotates in synchronism with barrel 25 and with selector switch 50 as above-mentioned. When the selector switch brush 11 reaches the grounded terminal as above described, the end limit switch 86 having meanwhile closed its contacts, the motor stops and reverses. During this reversal, neither of the cam barrels 25 or 25" reverses because of the intervening lost motion devices However, both stop ring drums |1' and I1" rotate clockwise until the previously selected pawl 26A'\` drops into the notch 23A' on the stop ring associated with the selected pawl. This effectively stops further rotation of stop drum barrel I1. However, barrel I1 is not stopped by the previously selected pawl 26A" because all the pawls are held in their latched position by the lip 68 of anvil 61. Since however, the drum I1 is stopped and since the drum I1" is rotated in a clockwise direction, the net result is that the member 6| rotates in a counterclock wise direction so as to again bring the ratchet 62 into engagement with anvil 61 thereby unlatching the selected pawl 26A". Consequently, the drum I1" continues vto rotate in a clockwise direction until it is positively stopped by the selected pawl 26A" entering the corresponding seen therefore, that the extent of counterclock-l wise rotation of the member 8| which is necessary to unlatch the pawls of unit #2, is a function of the extent of clockwise motion that the drum I1' undergoes before it is selectively stopped by the previously selected pawl 26A'. In other words,

until the member 9| causes unlatching of the pawls of unit #2, the shaft 12 continues to rotate the proper number of whole turns 21m. as determined by the extent of clockwise rotation of drum l1'. Thereafter, the fractional turn which is necessary to set the shaft 12 is determined by the partial rotation which the drum I1" undergoes before it is stopped by the selected pawl 26A". Thus unit #I determines the number of complete rotations that shaft 12 is to undergo, and unit #I determines the additiona1 fractional turn required for final setting of shaft 12.

It should be observed that in the particular condition illustrated in Figs. 4 and 5, the various parts indicate that portion of the operating cycle -during which the positioning elements of each of unit #I are running to some reference position which is referred to as the home position. When the mechanism is at rest as a result of having finally selectively set the shaft 12, the circuit is completed from battery 19 through relay 18 .to ground through brushes 11 and 14 whichresults rin opening of the motor power circuit. When it is desired to select a different preset shaft position, brush 14 is moved tothe contact corresponding to that position. This causes relay 16 to release and close its contacts 88, thereby closing the motor power circuit. Motor 4I begins rotating and drives units #I and #2, limit switch 49, and channel seeking switch 58 as described in connection with Fig. 4.

Shortly after rotation of channel seeking switch 50, begins, home limit Vswitch contact 86 closes and lead motor reverse relay 38 is operated. This causes reversal of motor 42. Channel seeking switch arm 50 remains 'in its selectively stopped position, but limit switch 49 rotates and causes the opening of home limit switch contacts 86.

In order to maintain rotation of motor 42,- motor reverse relay 8| is kept energized by a holding circuit traceable from grounded battery 19, conductor 88, winding of relay 8i, contacts 89, contacts 90 to ground. This holding circuit keeps motor reverse relay 8| energized until the rotation of limit switch 49 causes the end limit switch contact 18 to close. At this time `units #l and #2 have completed their selective positioning cycle and the tuning shaft is at rest at the desired selected angular position.

To establish a. new position of the driven shaft l2 corresponding to another desired channel, brush 14 of switch 13 is rotated to that channel. The dial which may be engraved on the front face of knob 20 of unit #I indicates the portion of a turn in which the operating cycle of unit #2 will be completed. A detailed description of this dial `will be found in Patent No. 2,378,941, granted June 26, 1945.

Bar I9 (Figs. 1 and 3) associated with this dial is rotated to unlock the stop rings of unit #2 cycle, the shaft-12 (Fig. 4')`.of the` tuning element is at rest within one turn of its nnal position which eliminatesl the necessity of manually turning shaft I4 of unit #2 through a number of revolutions. With this last method of setting, the exact position of shaft 12 is selected after completion of the tuning cycle, and in subsequent tuning cycles the shaft 12 will be reset to the same position every time the corresponding channel is selected by selector fswitch 13. In order to reduce the labor necessary in cranking unit #2 through a plurality of revolutions, unit #I may be set-up at the desired turn as indicated by its dial. The

`selector switch may thenbe momentarily moved from the contact corresponding to the channel on which set-up is desired. This starts a. tuning cycle which is completed with unit #2 within one turn of the nal position required. The locking bar of unit #2 may then be loosened, releasing the stop rings, and the shaft rotated to its exact position and relocked. The mechanism is then ready to stop the shaft at that position Whenever thatchannel is selected.

In order to prevent damage to the driven element 1I, a-lost-motion device 9| may be provided Ibetween shaft 12 and a suitable rigid member 92 so as to prevent over-travel of unit y#2 in the event of a faulty set-up cycle. This lost-motion device alsol establishes the home or terminal position of the stop .ring drum I1".

In order that the operations may be more I clearly followed, the following table illustrates and shaft I4" (Fig. 4) is rotated to the approxithe timing sequence` of a complete tuning or selecting cycle. i

1. Selector switch 13 is moved to a new position.

2. Ground is removed from brush 11.

3. Relay 18 falls out.

4. Motor 42 begins rotating.

5. Unit #I is driven counterclockwise toward its home position.

6. C'am drum 25' begins rotation.

'7. Unit #2 is driven counterclockwise after lost motion 43 takes up. 5l begins clockwise rotation.

8. Cam drum 25" begins rotation. Selector switch 50 begins rotation in synchronism with 25 and 25".

9. Limit switch 49 closes contact 86.

10. Brush 11 of switch 58 contacts the grounded switch position.

11. Reversing relay 8i pulls in.

12. Drive motor 42 reverses.

13. 25', 25", and 50 stay in position. Stop ring I1' is rotated in a clockwise direction. Limit switch 49 is rotated in a clockwise direction.

14. Stop ring I1 sets up with the pawl falling into the notch.

15. Stop ring I1 begins rotation in a clockwise direction.

Stop ring I1" sets up to desired position. Limit switch 49 closes contact 18.

Relay 16 pulls in.

Motor stops. Completing tuning cycle.

While there has been here described a preferred embodiment of this invention, it is understood that various changes and modifications may be made therein without departing from the scope of the invention.

What is claimed is:

1. An arrangement for selectively positioning a rotatable shaft such as a control shaft for radio apparatus and the like which shaft undergoes more than one complete rotation-before arriving at a certain final. selective angular orientation,

Pawl anvil 61 releases selected pawl 26A'.A

comprising a first automatic shaft positioning unit arranged to act as a turn controlling device to determine the number of complete rotations for said control shaft, a second similar automatic shaft positioning unit arranged to control the additional fractional rotation of said shaft to bring it to said final selective orientation, and a differential gear system operated under control of both said units to cause said shaft to be selectively stopped by the second unit only after said shaft has executed a number of complete rotations under control of the first unit.

2. An arrangement for selectively positioning a rotatable shaft such as a control shaft for radio apparatus and the like which shaft undergoes more than one complete rotation before arriving at a certain nal selective angular position, comprising a rst automatic shaft positioning unit arranged to act as a turn controlling device to control the number of complete rotations for said control shaft, a second similar automatic shaft positioning unit arranged to control the additional fractional rotation of said shaft to bring said control shaft to said final selective position, and means interlinking said units so that the first unit controls the number of complete rota'.

relative selective movements of said stop ring assemblies for determining the number of complete rctations of said shaft.

5. An arrangement for selectively positioning a rotatable shaft such as a control shaft for radio apparatus and the like which shaft undergoes more `than one complete rotation before arriving at a certain final selective angular orientaat a certain final selective angular position, coml prising a rst automatic shaft positioning unit arranged to act as a turn controlling device to determine the number of complete rotations for said control shaft, a second similar automatic shaft positioning unit arranged to control the additional fractional rotation of said shaft to bring said control shaft to said nal selective position, and means interlinking said units so that the first unit controls the number of complete rotations said shaft undergoes before said shaft is' selectively stopped by said second unit, the lastmentioned means including a differential gear train and a movable member controlled thereby for controlling the said second unit, the said gear train having one section connected to rotate in timed relation with the said first unit and another section connected to rotate in timed relation with the said second unit, said movable member having its position controlled by the relative rotations of said gear sections.

4. An arrangement for selectively positioning a rotatable shaft such as a control shaft for radio apparatus and the like which shaft undergoes more than one complete rotation before arriving at a certain final selective angular position, comprising a first automatic shaft positioning unit arranged to act as a turn controlling device to control the number of complete rotations for said control shaft, a second similar automatic shaft positioning unit arranged to control the additional fractional rotation of said shaft to bring said shaft to said final selective position, each of said units including a, selectively rotatable stop ring assembly, and differential means interlinking said units, said differential means having a selectively positioned element which is responsive to the tion, comprising a first automatic shaft positioning unit arranged to act as a turn controlling device to control the number of complete rotations for said control shaft, a second similar automatic shaft positioning unit arranged to control the additional fractional rotation of said shaft to bring it to said final selective orientation, each of said units including a selectively rotatable stop ring assembly, and a cooperating shiftable pawl assembly; a differential gear train coupled to the stop ring assemblies of both units,vand a control member for the stop ring assembly of the second unit said control member having its extent of movement and direction of movement controlled by the differential gear of said differential gear train.

6. An arrangement for selectively positioning a rotatable shaft such as a control shaft for radio apparatus and the like, which shaft undergoes more than one complete rotation before arriving at a certain final selective angular position, comprising a first automatic shaft positioning control unit arranged to act as a turn-controlling device to control the number of complete rotations for said control shaft, a second similar automatic shaft positioning control unit arranged to control the additional fractional rotation of said shaft to bring it to said final selective position, each of said units including a selectively rotatable stop ring assembly and a selectively movable pawl assembly, there being one pawl for each stop ring, means to move a selected pawl to a preliminary selected position, means to rotate the associated stop ring assembly to a selected position to enable said pawl to move to its final position where it stops the said associated assembly, and means coupled to the stop ring assemblies of both units whereby the stop ring assembly of the second unit continues rotating until the stop ring assembly of the first unit is selectively stopped and until the stop ring of the second unit is likewise .selectively stopped by its associated selected pawl assembly.

7. An arrangement according to claim 6 in which each of said automatic units includes a rotatable cam barrel whose angular orientation determines the selection of an individual one of the associated pawls.

8. An arrangement for selectively positioning a radio control shaft and the like which shaft vundergoes more than one complete rotation before arriving at a certain final selective angular position, comprising a first automatic shaft-positioning control unit, a second similar automatic shaft-positioning control unit, each of said units including a selectively rotatable stop ring assembly, means to limit the rotation of the stop 11' Y to the stop ring assembly of the second unit, each unit having a series of selectively shiftable pawls for selectively stopping the associated stop ring unit, a member which is differentially controlled by the movement of the stop ring assemblies of the first and second units, said member normally rendering the pawls of the second unit from moving into stopping relation with the associated stop rings, and means responsive to the selective stopping of the first unit for causing said member to unlatch said pawls of the second unit and thereby to allow said pawls of the second unit selectively to stop the associated stop ring.

assembly.

9. An arrangement for automatically controlling the positioning of a control shaft, comprising a rst automatic control unit. a second automatic control unit each of said units having a pair ofV rotatable selector drums one drum comprising a series of pre-settable stop rings and the other drum comprising a series of selectable pawl actuating cams one for each of said stop rings, a series of oscillatable pawls for each cam drum and cooperating with the associated stop ring drum to stop it in a selected angular position, means to limit the rotation of the stop ring drum of the rst unit to one complete rotation, a common reversible electric motor coupled through slip clutch means to the stop ring drums of both said units, means to start said motor to drive the cam drum of the rst unit in a homing direction, means selectively to stop the stop ring drum of the rst unit when the associated cam drum reaches a selected angular orientation but Without simultaneously stopping the stop ring drum of said second unit, a common locking latch for all the pawls of the second unit and normally preventing said pawls from stopping the stop ring drum of said, second unit, releasing means for said locking latch, means to move said releasing means away from said latch to an extent determined by the particular pawl which is selected in said first unit, and means effective in response to the selective stopping of the stop ring drum of the rst unit to move said releasing means to unlock said latching means and thereby determine the number of complete rotations for the stopping ring drum of said second unit, said control shaft being connected to the stop ring drum of said second unit.

10. An arrangement of the character described, comprising a rst automatic control unit, a second automatic control unit, each of said units being of the stop ring drum and selectable stopping pawl type, a selector switch, means for driving both said units and said switch from said motor, means controlled by said switch for selecting a stopping pawl in each of said units, time delay means for delaying the selective action of the second unit with respect to the rst unit, a latching device common to all the pawls of the second unit for normally preventing them from stopping the stop ring drum of the second unit, means responsive to the selective stopping of the said rst unit for unlatching said latching device after the stop ring drinn of the second device has made a number of complete rotations as determined by the extent of selective rotation of the stop ring drum of the rst unit, and a master shaft to be controlled and connected to the stop ring drum of said second unit.

11. An arrangement of the character described, comprising a rst automatic control unit, a second automatic control unit, each of said units having a rotatable drum which is adapted to be 14 selectively stopped in any demred angular orientation, a plurality oi' selectively operable stops for the drums of each unit. a latch common to all the stops for the second drum and normally holding said stops out of stopping engagement with said drum, a shiftable member controlled.- jointly by the relative rotations of the drums o! the first and second units for unlocking said latch means to enable the drum of the second unit to make a plurality of complete rotations, and selector switch means for controlling the selecv tion of a stop member in the first unit and for controlling the selection of a stop member in the second unit.

12. An arrangement according to claim 11 in which said shiitable member is rotatably mounted on a shaft which is connected to the differential gear of a differential gear train, the remaining' ygears of the differential gear train' being coupled respectively to the drums ofthe said iirst and second units. ,A

13. An arrangement according to claim 11 in which said ilrst dru'm is of the homing type and is arranged to undergo a homing rotation for the purpose of selecting one of its associated stops and in a reversed direction for the purpose of being selectively stopped by the said selected stop..

14. An arrangement according to claim 11 in which the first unit is provided with an additional rotatable cam drum which is coupled to the shaft of the stop drum through a lost motion connection and an additional lost motion connection is provided between the motor and the second unit.

15. An arrangement according to claim 11 in which said shiftable member is in the formof a ratchet pivotally mounted on a rotatable disc, said disc being connected to the differentially responsive member of a differential gear train, the remaining gears of said train being connected respectively to Athe drum shafts of saidrst and second units.

16. An arrangement of the character described, comprising a main drive shaft, a master shaft to be controlled, a plurality of similar automatic control units for controlling the positioning of said master shaft, a selector switch and a limit switch driven from said main driving shaft, a selective stop drum in each of said automatic control units, a differential gear system operated in response to the relative rotations of the said drums in said units, a lost motion device between the first and second units for delaying the beginning of the selective movement of the second unit a predetermined time interval after the beginning of the selective movement of the rst unit, means controlled by said selector switch for selectively determining the extent of rotation of the stop drum in said first unit, and means controlled by the extent of movement of said stop drum in the rst unit and the extent of rotation of said shiftable member for determining the number of complete rotations for the stop drum of the second unit.

17. An arrangement of the character described, comprising a master shaft which is to be rotated more than one complete rotation to a final selective position, a ilrst automatic shaft control unit, a second automatic shaft control unit, each of said units comprising a stop ring drum and a selector cam drum and a plurality of stopping pawls for stopping the stop ring drum under control of the setting of the associated cam drum; means to limit the rotational movement of the stopring drum of the first unit to less than one complete rotation whereby the setting of said stop ring drum of the rst unit determines the number of complete rotations of the stop ring drum of the second unit, and selector switch means for selectively stopping the stop ring drums of both units when the said master shaft has arrived at its desired final selective position, said master shaft being connected to the stop ring drum of the said second unit.

18. An arrangement of the character described,

,comprising a reversible electric motor, a first shaft section driven by said motor, a second shaft section driven from the first shaft section through a lost motion connection, a stop ring drum driven through a slip-friction clutch from the said first shaft section, another stop ring drum driven through a slip-friction clutch from the said second shaft section, a selective cam drum driven through a lost motion connection from the first shaft section, another selective cam drum driven through a lost motion connection from the second shaft section, selectively operable stops controlled by the first cam drum for selectively stopping the first-mentioned stop ring drum, another set of selectively operable stops controlled by the second-mentioned cam drum and arranged to selectively stop the second-mentioned stop ring dr and differential control means for rendering the last-mentioned set of selective stops ineffective to stop said second stop ring drum until said second stop ring drum has undergone a number of complete rotations determined by the selective setting of the first-mentioned stop ring drum.

19. An arrangement according to claim 18 in which said first-mentioned stop ring drum is connected to a limit control device for limiting its rotation to approximately 360 degrees.

20. An arrangement according to claim 18 in which both of said shaft sections are driven from a common reversible electric motor, said motor having a start circuit which is controlled by said selector switch and a limit control switch which is driven by said first shaft section, a motor re- .versing circuit also controlled by said selector switch and by said limit control switch, and means lfor causing said motor to rotate in one direction to restore the stop ring drum of the said first unit to a homing position to set the associated cam drum in selective position and for reversing the directionof rotation of said first stop ring drum until it arrives 'at selective stopping position.

21. Apparatus for selectively positioning a control shaft which is arranged to undergo more than one complete rotation in arriving at its final selected position, comprising a first shaft control unit arranged to execute less than one complete rotation, a reversible electric motor, a second shaft control unit driven from said motor and provided with a lost motion mechanism for delaying the beginning of its control cycle for a predetermined time interval after the beginning of the control cycle of the first unit, said second unit being arranged to execute more than one complete rotation, each of said units including a plurality of devices providing selectable stop combinations, a differential device jointly controlled by the shafts of both said units, a device for holding and releasing the selective stopping means in said second unit, the last-mentioned device being connected to the differentially movable element o f said differential means, an end limit switch responsive to the complete rotation in either direction of said first unit, a multi-point selector switch having a plurality of contacts one allotted to each selective stopping position for said rst unit, means to operate said limit switch and said selector switch from said motor, circuit means controlled by said motor for causing the first unit to be rotated in one direction to a select stop combination therein and for causing the second unit to be rotated to select a stop combination therein, other circuit means for thereafter causing the motor to reverse its direction of rotation to reverse the direction of rotation of said first unit until the selected stop combination of the first unit is effective to stop the first unit in its reversed motion, while allowing continuous rotation of the second unit until the stop combination of said second unit is effective to stop said control shaft in its final selected position.

22. Apparatus according to claim 21 in which said differential means includes a planetary gear arrangement in which the sun gear is connected to the shaft of the second unit, planetary gears are connected to the shaft of the first unit, and the ring gear is connected to said stop-holding and releasing means.

RICHARD W. MAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,246,050 Leishman June 17, 1941 2,351,185 Boterweg et al June 13, 1944 2,391,470 May Dec. 25, 1945 

